Method and apparatus for producing coins



Aug. 29, 1967 c. F. STEGMAN, SR 3,338,084

I METHOD AND APPARATUS FOR PRODUCING C OIN S I Filed Feb; 25, 1965 3Sheets-Sheet l I ZN 1&3;

g- 29, 1967 c. F. STEGMAN, SR 3,338,084

METHQDAND APPARATUS FOR PRODUCING COINS Filed Feb. 23, 1955 Aug. 29,1967 c F. STEGMAN, SR 3,338,034

- METHOD AND APPARATUS FOR PRODUCING cows v Filed Feb. 23, 1965 5Sheets-Sheet 5 nnn n Patented Aug. 29, 1967 3,338,084 METHOD ANDAPPARATgS FOR PRODUCING COIN Clittord F. Stegman, Sr., 5811 Twin OaksDrive, Cincinnati, Ohio 45224 Filed Feb. 23, 1965, Ser. No. 434,329 3Claims. (Cl. 72-333) This invention relates to a method and apparatusfor manufacturing coins and tokens and more particularly, the inventionis directed toward improving the efliciency of the manufacture of coinsand tokens.

Reference will be made herein to the manufacture of coins but it is tobe understood that the invention is equally applicable to tokens,medallions and like small, flat, metallic objects having indiciaembossed in the surface thereof or metal removed from portions thereof.

Coins have been manufactured for many years without any fundamentalchanges in either the method or the apparatus for making them. Ingeneral, the process begins with long strips of material received from arolling mill in coils. The width of the strips varies depending upon thesize and number of coin blanks to be punched out of the strip with eachstroke of the press. The strip is fed incrementally into a blankingpress by which coin blanks are punched out. These blanks are cleaned anddeburred usually by revolving them in tumbling barrels together withdeburring and brightening materials. The blanks may then be edge-rolledor otherwise preformed, the edgerolling being performed in apparatuswhich rolls the edges of the coins to a precise diameter.

The thus formed blanks are then subjected to a coining operation. Inthat operation each blank is confined in a constricting collar betweentwo embossing dies. The dies are brought together to cmboss the coin oneach side, the constricting collar restraining the outward flow ofmaterial and thereby determining the outside diameter of the coin. Thecoining apparatus and the manner in which the coins are fed to theapparatus is widely varied but in the various machines, the coiningthrough the use of two dies operating in a constricting collar remainsthe same.

Among the disadvantages of the present practices is the requirement fordistinct blanking apparatus, deburring apparatus and. coining apparatuswith handling of the coins required between operations all of whichresults in a low volume output based on the capital investment ofmachinery and the labor involved in the operations. In the production ofcoin money, these factors have resulted in coin shortages.

An objective of the apparatus has been to provide a single machine whichreceives strip stock at its input and delivers finished coins at itsoutput. To this end, the invention contemplates the reversal of theoperations presently constituting the present practice of making coinsto the extent that the coin is embossed or otherwise treated to form itwhile in the strip form and, after the coin is formed, blanking the coinout of the strip. Through this reversal of the sequence of theoperations performed on the material certain intermediate steps of theprior practices are eliminated. For example, it is not necessary to sizethe coin properly so that it can be received in the constricting collarof the coining apparatus for the strip stock surrounding the coinconstitutes its own constricting collar and exerts a suflicient lateralconstricting force to cause the metal in the stock to flow into theconfigurated recesses of the dies under the embossing pressure.

It has been another objective of the invention to provide substantiallyuniform constricting pressure and hence unidirectional fiow of metalduring the embossing operation by forming transverse slots in the stockbetween areas which are to be embossed. The slots permit flow of metallongitudinally of the strip to substantially the same extent as ispermitted transversely of the strip, the dimensions of the excessmaterial transversely and longitudinally around each coin beingapproximately the same. This transverse slotting to create unformity inthe constricting force of the surrounding metal appears to be criticalto the success of the apparatus; for in treating thick metals, a lack ofuniformity in the flow of metal tends to distort the surfaceconfiguration of the embossed coin.

If it is desired to produce a superior quality coin, the coins deliveredfrom the coining and blanking apparatus described above may beautomatically fed into an attached grinding device for diameter sizingas well as apparatus for serrating the edges of the coins. Thus, it ispossible to produce even the finest quality coins with a continuous flowof material and with minimal handling of the stock as it moves throughits successive stages of operations.

The several features of the invention will become more readily apparentfrom the following detailed description taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a perspective view of the embossing and blanking apparatus ofthe invention,

FIG. 2 is a disassembled perspective view of one embodiment of the diesand strip feeding mechanism,

FIGS. 3 and 4 are cross-sectional views of the die structure showing theoperations performed on the stripping stock,

FIGS. 5 and 6 are plan views of strip stock illustrating sequences ofoperations which may be performed on the stock through the invention,and

FIG. 7 is a diagrammatic plan view of strip stock formed through analternative embodiment.

FIG. 1 shows a press 10 in which upper and lower dies 11 and 12respectively of the present invention are mounted. The apparatus has abase 13 on which a fixed platen 14 is mounted and a verticallyreciprocating ram 15 on which a movable platen 16 is mounted. The dies11 and 12 are fixed to the respective platens and are guided into properregistry with each other by guide pins 17 which are located at the fourcorners of the platens.

Incased in a housing 20 is operating mechanism for reciprocating the ram15. The stroke of the ram is such that in its uppermost position itraises the upper die a distance to permit strip stock 21 to be fedbetween the dies and in its lowermost position it brings the upper dieto a position in which it is precisely spaced from the lower die by thatdistance required for the proper embossing of the coins. The raw stripstock 21 is fed intermittently by a feeding mechanism 22 between theupper and lower dies 11 and 12 respectively in timed relation to thereciprocation of the upper die so that as the upper die is raised, thestock is fed a distance equal to the centers of adjacent coins beingformed.

Except for the die structure, the press and feeding apparatus is knownand apparatus selected from a number of difierent types can be used.

Representative die structure and strip feeding mechanism is illustratedin FIG. 2. The lower fixed platen 14 has the guide pins 17 fixed to it,the guide pins projecting vertically above the upper surface of theplaten. The upper platen 16 is fitted at its corners with the bearings25 having holes 2 6 therethrough through which the guide pins 17 pass.The bearings 25 are preferably of the ballin-race variety which assuresprecise alignment of the dies as the upper platen is reciproated inrespect to the lower platen. The upper platen carries a cam lug 27having an inclined cam surface 28 and a vertical dwell surface 29 whichare engageable with a slide 30 reciprocably mounted in a fixed housing31. The housing 31 carries a pair of upper and lower gripping wheels 32,only the upper wheel being shown. Each wheel is attached by means of anoverrunning one-way clutch to a pinion gear 33 which meshes with a rack34 on the slide 30. The one-Way clutch permits the pinion 33 to drivethe gear 34 positively when the slide 30 moves toward the left as viewedin FIG. 2 but when the slide moves to the right, the pinion gear rotatesfreely with respect to the gripping wheel 32. V

A compression spring 35 engages the slide and urges it toward the leftas viewed in FIG. 2. In the operation of the feeder 22, on the downwardstroke of the upper platen 16 the cam lug 27 drives the slide toward theright compressing the spring 35. Because the pinion can turn freely withrespect to the gripping wheels 32, there is no rotary movement of thefriction wheels during this portion of the operation. On the upwardstroke, the movement of the cam lug 27 out of the way of the slide 30permits the compression spring 35 to expand driving the slide 30 towardthe left. The rack 34 carried by the slide rotates the pinion 33 which,through the clutch causes the wheels 32 to rotate thereby driving thestrip stock longitudinally with respect to the dies.

The lower die 12, in the illustrated embodiment, has a female piercingdie 37 having an elongated transverse slot 38 terminated in two holes39. The upper die 11 has a mating piercing punch 40 which when driventhrough the strip stock 21 into the female die 37 forms a stressrelieving slot 41 as well as two pilot holes 42 in the strip stock.

As shown in FIGS. 3 and 4, a chute 43 is provided below the slot 38 andholes 39 through which the scrap pieces punched out of the strip areconveyed away. Adjacent the piercing dies is an unused space indicatedat 46 whose length is equal to the distance of each advance of the stripstock. Adjacent that space are, sequentially, a preforming station 47,an embossing station 48 and a blanking station 49. Each of thesestations has, at its four corners, pilot pins 50 in the upper die 11 andmating holes 51 in the lower die 12. The unused space 46 permits thestock to be advanced to a position in which the pilot holes 42 areengageable by the pilot pins 50 at four corners surrounding the area tobe formed at the preforming station, thereby assuring accuracy in thealignment of the dies with the stock at that station as well as atsucceeding stations. The preforming station 47 is constituted bypreforming embossing dies 53 and 54 on the lower and upper dies 11 and12 respectively. The preforming dies are not always necessary but whenthe complete embossing of the coin requires substantial metal flow tocreate the relief in the surface of the metal, one

' or more preforming dies may be employed to move masses of metal into aposition for the final embossing operation. In the illustratedembodiment the preforming dies 53 and 54 are adapted to form aperipheral shoulder or border in the area indicated at 57 on the dies.

The embossing station 48 adjacent the preforming dies 53 and 54 isconstituted by a lower embossing die 55 and an upper embossing die 56.These dies compress the metal in the blank to perform the finalembossing operation.

The blanking station 49 adjacent the embossing dies 55, 56 comprises :alower female blanking die 58 and an upper blanking punch 59 whichseparates the embossed coin from the strip stock. A chute 60 (FIGS. 3and 4) is provided below the female die 58 to receive blanked out coinsand to convey them away for further handling.

In the upper dies, the punches 40 and 59 and the embossing dies 53 and56 are mounted on an upper die shoe 63. which in turn is fixed to theupper platen 16. The pilot pins 50 are mounted on the upper die shoe 63be tween the successive stages of punches and preforming or embossingdies so that each operating station has four pilot pins around it. Thelower die 12 has corresponding holes 51 to receive the pilot pins 50.The pilot pins are tapered and are adapted to engage the pilot holes 42formed in the strip stock by the punch 40. The cooperation of the pilotpins 50 with the pilot holes 42 positively precisely locates the stockin the proper position with respect to the dies 11 and 12. V

The lower die 12 has a guide plate 64 mounted on its upper surface, theguide plate 64 having a downwardly facing channel 65 which receives thestock and guides it in its traverse through the dies. The width of thechannel 65 is sufiiciently greater than the width of the strip stock topermit the strip stock to flow transversely without binding against thesoles of the guide channel. The channel should be narrow enough,however,

to limit the sidewise movement of the strip so that the pilot holes 42will always be in position to be engaged by the pilot pins 50. Arectangular opening 66 is formed in the surface of the guide plate 64 toexpose the lower die sections to the upper die sections for theperformance of the required operations.

A stripper plate 67 is secured to the upper die shoes 55 by pins 68which are slidable in the die shoe. The pins are headed at their upperends to limit their downward movement and are fixed at their lower endsto the stripper plate. Compression springs 69 surrounds each pin to urgethe stripper plate 67 in a downward direction. The stripper plate 67 hasholes 70, 71, 72 and 73 through which the piercing punch 40, the dies 53and 56 and the punch 59 may pass. The stripper plate has longitudinalgrooves 74 presenting an elongated central foot 75 which engages thestock while the sides of the guide plate 64 are received in the grooves74.

The operation of the invention is illustrated by reference to FIGS. 3and 4. In FIG. 3 the upper platen 16 is in its raised position and thestrip stock 21 has been advanced one stage by the gripping wheels 32 ofthe feeding mechanism 22. When the platen 16 is driven to its lowermostposition illustrated in FIG. 4, the first operation performed on thestock is the punching out of the slot 41 and the pilot holes 42 by thepiercing punch 40. The platen 16 is raised, the strip 21 is fed anotherincrement, and the platen 16 is lowered. As the platen is lowered, thefirst pair of pilot pins 50 engage thepi-lot holes 42 previously punchedon the stock thereby precisely locating it with respect to the formingdies 11 and station 47, the upper preforming die 53 compresses the stockagainst the lower performing die 54 to effect an initial shaping or fiowof the metal toward the general configuration ultimately desired in thefinishing coin, the formation of a shoulder 57 being illustrated by wayof example.

As the platen is driven downwardly in each operation, the stock is'firstengaged by the pilot pins 50 to provide its precise positioning and isthereafter engaged by the stripper plate 67 under the ratherconsiderable pressure of the compression springs 69. Thereafter thepunches and dies perform their operations. In the upper stroke of theplaten 16, the stripper plate 67 remains in engagement with the stockunder the pressure of the springs 60 until the punches and dies havebeen raised out of engagement with the stock. Thereafter the stripperplate is raised with the .die structure out of the way of the strip sothat it can be fed. The dwell surface 29 on the cam lug 27 preventsmovement of the slide 30 in a directionembossing stage. In that stage,the upper embossing die 56 compresses the strip against the lowerembossing die 55 to complete the final formation of the surfaceconfiguration of the coins; In this operation it is critically importantthat under the pressure of the dies the metal be permitted to flowuniformly in transverse and longitudinal directions. The width of thestrip between the deformed portion and longitudinal edge, indicated at80, of the strip permits flow transversely and the relief by the slot 41permits flow longitudinally as at 81. It should be noted that the Widthof the strip is approximately equal to the longitudinal space betweenthe slots 41. If the apparatus were designed to provide formingoperations side by side on a wide strip to form two or more coinssimultaneously, it would be necessary to provide longitudinal slots 82between laterally adjacent coins to permit flow of the metal in thetransverse direction. A strip formed in this manner is illustrated inFIG. 7.

In addition to permitting uniformity of flow of the metal beingdeformed, the stock surrounding the coin provides a critically importantconstricting collar which restricts planar or lateral flow, therebycausing the metal to be driven up into the recesses of the dies underembossing pressure.

The platen 16 is raised, the strip is advanced and the platen is loweredto effect the final operation in the formation of the coin. In thatoperation, the punch 59 engages the embossed coin and drives it throughthe female die 58 to separate it from the strip 21. The coins drop outof the lower die and into the tubular chute 60 in which they areconveyed away for further processing or for packaging.

In the foregoing, the operations have been described as a series ofstages of operations. It should be understood that after the strip hasbeen fed through the die all stages are performed simultaneously on thestrip as indicated in FIG. 4. The condition of the strip after eachstage of operation is illustrated in FIG. 5.

As has been indicated above, the preforming operation may not berequired. On the other hand, more forming operations than thosedescribed may be employed. For example, as illustrated in FIG. 6, thestrip may be formed sequentially as follows.

First, the transverse slot 41 and pilot holes 42 are formed. Second, thestock is preformed to form a border or shoulder 85. Third, the stock isfurther preformed to move masses of metal to positions indicated at 86.Fourth,

a coining operation is performed at 87. Fifth, the final embossing stageis performed at 88. Sixth, the metal is pierced to remove portions at 89as in the formation of tokens and the like. And last, the coin isseparated from the stock as at 90.

I claim: 1. The method of manufacturing coins comprising the steps of,

forming spaced laterally extending slots in strip stock, embossing thestrip stock between said slots to form the coins surface configuration,and punching the embossed coin out of the stock. 2. The method ofmanufacturing coins comprising the steps of,

forming spaced laterally extending slots in strip stock and at least oneline of longitudinally extending slots, embossing the strip stockbetween said laterally extending slots and on each side of said line ofslots to form the coins surface configuration, and punching the embossedcoin out of the stock. 3. The method of manufacturing coins comprisingthe steps of,

punching laterally extending spaced SlOts in strip stock, embossing thestrip stock in an area midway between said slots and the longitudinaledges of said strip stock to form the coin surface configuration, thedistance between the periphery of the coin and said edges and slotsrespectively being substantially the same thereby forming a constrictingcollar applying substantially uniform constricting pressure againstlateral flow of the material in the coin, and punching the embossed coinout of the stock.

References Cited UNITED STATES PATENTS 589,595 9/1897 Draher 72-333 X604,376 5/1898 Egge 72-404 X 790,462 5/1905 Smith 72-333 2,062,04411/1936 Stoffel 72333 WILLIAM W. DYER, IR., Primary Examiner. LEONIDASVLACHOS, Examiner.

1. THE METHOD OF MANUFACTURING COINS COMPRISING THE STEPS OF, FORMINGSPACED LATERALLY EXTENDING SLOTS IN STRIP STOCK, EMBOSSING THE STRIPSTOCK BETWEEN SAID SLOTS TO FORM THE COIN''S SURFACE CONFIGURATION, ANDPUNCHING THE EMBOSSED COIN OUT OF THE STOCK.